Anyone replace ABS Control Module/Brake Booster?? - Page 4 - Toyota 4Runner Forum

rwh963 · 08-13-2022, 09:46 AM

also, looks like a useful document: Error Codes TOYOTA & SELF-DIAGNOSTICS - Wiring Diagrams

Jakeepoo3 · 08-13-2022, 05:51 PM

Quote:

Originally Posted by rwh963

jp3, looking at your toyota service manual link, looks like it is purely ABS (VSC is on just because of ABS). for ABS then, we have: 1421, 1422, 1423, 1424.

That makes sense. All those codes relate to the master cylinder pressure sensor and master cylinder pressure control sensor. So you would want to test that circuit and the sensors.

rwh963 · 08-13-2022, 06:59 PM

are those replaceable parts? jus,ped on a toyota part site and came up empty. bad feeling they are imbedded in the master cylinder assembly.

Jakeepoo3 · 08-15-2022, 09:45 AM

Quote:

Originally Posted by rwh963

are those replaceable parts? jus,ped on a toyota part site and came up empty. bad feeling they are imbedded in the master cylinder assembly.

They are inside the abs control valve/pump assembly, unfortunately. I've never rebuilt one myself but I'm sure that's an option. There could be a problem in the actual wiring/circuit outside of the abs assembly. (Short circuit, open ground, loose connector pin) That's what I would hope for. If you feel like it you can test the circuitry to make sure you're getting a signal from the pressure sensor to see if it's working or if the stop lamp circuit is out of whack.

alia176 · 08-16-2022, 01:12 PM

Quote:

Originally Posted by rwh963

long time issue here. took 4runner (2007 230k v6 4wd one owner) to the dealer in March. after $300 in diagnostics, they determined my issue is with the ABS control module back feeding into the system.

PLEASE REFERENCE THREAD: Brake lights constantly on?

afterwards, i examined the plastic encased module and noticed impact backs in the case. very weird. did it let in moisture for years and damage the computer boards?? no idea what happened.

since, been trying to figure if there is an alternative answer. even at discount, a new module is about $800 (P/N 47217-35010), new Master cylinder with booster is $1200 (P/N 47025-35070). add labor to that.

backstory: the original master /abs module was replaced any about 111k miles because of constant squealing. put in a used unit that had about 70k miles on it. things were fine until the past year or so (based on people telling me my brake lights are constantly on).

so, after several months, i'm am considering biting the bullet and replacing the unit again. now, i'm wondering how common this issue is. i think economically the best bet is to go with a used unit that includes the master cylinder ($1200 part), and having it independently installed. maybe three hours labor charge. probably in over $500. it is a crapshoot. i'm having to go on the dealer's conclusion. could be wrong.

does anyone have experience with these units, and their installation?

My aplogies for not reading the entire thread but I can add something. I picked up an used unit from a buddy who owns a 100 series LC and it matches mine. The only thing that wears out, from what I can tell, is the motor brushes and bearing. The motor is constantly pressurizing the brake system so it makes sense that those two items would wear out. I suppose the solenoid valve is also an wear item but they're not operating on a continuous duty cycle. Besides, they're just stupid on/off valves which aren't typically known to fail. Perhaps a piece of debris in the brake fluid would prevent a valve from closing shut completely but that's a stretch.

I took apart the spare unit and noticed the brushes weren't that worn down. You might recall that the motor sits vertically and the bearing that sits at the bottom had way more crud fell on top of it. Someday, I may replace both bearings and brushes, clean up the commutator then put it back on the shelf as a spare but good unit.

I'm disappointed that I didn't more pics but I have a pic of the actual motor shaft bearing for future reference.

I guess the moral of the story is if you have your spare motor, take it apart and see what's up. The chances of an electronic part like an ECU going bad is close to zero. Toyota simply makes robust parts that lives a long time.

I hope this helps!

alia176 · 08-16-2022, 01:16 PM

Quote:

Originally Posted by Jakeepoo3

Those sensors within the master are actually the ones that signal the stop lamps on or off when they detect hydraulic pressure within range. I believe I posted that diagnostic procedure already also.

This is a VERY interesting statement. While I was wheeling with my daughter who was behind me, she did say that the brake lights were coming on when ATRAC was doing its thing. I asked her on the radio if they were coming on and she confirmed it.

Now I know how the system knew when to activate the rear brake lights.

Thank you for this!

rwh963 · 08-16-2022, 06:04 PM

Quote:

Originally Posted by Jakeepoo3

They are inside the abs control valve/pump assembly, unfortunately. I've never rebuilt one myself but I'm sure that's an option. There could be a problem in the actual wiring/circuit outside of the abs assembly. (Short circuit, open ground, loose connector pin) That's what I would hope for. If you feel like it you can test the circuitry to make sure you're getting a signal from the pressure sensor to see if it's working or if the stop lamp circuit is out of whack.

so, if you are a betting man, it sounds like you would put your money on needing to replace the complete unit (master cylinder/module), which is what was done at 111k miles with a used unit w/85k? that would put me back to the beginning, and basically back to the dealer diagnostic of abs module failure. the module being $800 and the whole unit being $1200, they say they typically just replace the whole thing.

that puts me back to hunting for a low mileage unit that either an independent or dealer would install (i've had luck labor matching). looking at $700-$800.

Jakeepoo3 · 08-17-2022, 04:35 PM

Quote:

Originally Posted by rwh963

so, if you are a betting man, it sounds like you would put your money on needing to replace the complete unit (master cylinder/module), which is what was done at 111k miles with a used unit w/85k? that would put me back to the beginning, and basically back to the dealer diagnostic of abs module failure. the module being $800 and the whole unit being $1200, they say they typically just replace the whole thing.

that puts me back to hunting for a low mileage unit that either an independent or dealer would install (i've had luck labor matching). looking at $700-$800.

Yeah, it sucks bud, that vicious cycle. I don't know anything about dealing with a mechanic or labor costs.. after confirming it's 100% not something simple in the circuitry it's a tough call for you.

rwh963 · 08-18-2022, 08:51 AM

well, i'm no worse off in a way. the issue is not affecting my drivability. but needs to be fixed. i'll shop for a good used unit first. there may be some decent resale value in mine to offset that expense.

good news, i don't have a car payment, so that saves $3-400/month.

need new tires, pre-mature wear. called the place i purchased from (discount tire direct). they, without question, helped me achieve a nearly $100/tire credit, so ordered new set for $400. so that saves some $$.

front brakes and outside CV axle on the list.

also, for the past several days the acceleration hesitation has not appeared. not sure if it has anything to do with topping off the fuel tank for the first time in a long time. thoughts on that?

alia176 · 08-18-2022, 12:43 PM

Quote:

Originally Posted by rwh963

well, i'm no worse off in a way. the issue is not affecting my drivability. but needs to be fixed. i'll shop for a good used unit first. there may be some decent resale value in mine to offset that expense.

good news, i don't have a car payment, so that saves $3-400/month.

need new tires, pre-mature wear. called the place i purchased from (discount tire direct). they, without question, helped me achieve a nearly $100/tire credit, so ordered new set for $400. so that saves some $$.

front brakes and outside CV axle on the list.

also, for the past several days the acceleration hesitation has not appeared. not sure if it has anything to do with topping off the fuel tank for the first time in a long time. thoughts on that?

Not sure if you read my reply up above but see if it's the motor that's the issue. Perhaps the brushes have worn down too much?

Anyway, I feel your frustrations amigo.

rwh963 · 08-18-2022, 04:41 PM

Quote:

Originally Posted by alia176

Not sure if you read my reply up above but see if it's the motor that's the issue. Perhaps the brushes have worn down too much?

Anyway, I feel your frustrations amigo.

hello,

yes, i did see your contribution. i'm not sure what you are suggesting. it looks like the alternator? does this have something to do with the master cylinder unit and brake lights?

alia176 · 08-18-2022, 05:15 PM

Quote:

Originally Posted by rwh963

hello,

yes, i did see your contribution. i'm not sure what you are suggesting. it looks like the alternator? does this have something to do with the master cylinder unit and brake lights?

No sir, that pic is of the actual ABS motor! I took my spare one apart and made the observations I listed in the post.

Anyway, might be worth a shot!

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